BMD T-Score (Left Total Hip)

Hip fractures are not just a broken bone. They carry the highest risk of disability, hospital readmission, and death of any common bone break, and most happen in people who had no idea their bones were thinning.

Your left hip T-score (a number from a low-dose hip scan called DXA, short for dual-energy X-ray absorptiometry) is the most direct read on whether your hip bone can withstand a fall. Each one-point drop in this number roughly doubles your hip fracture risk.

What Your T-Score Actually Means

The T-score is not a hormone or a protein. It is a comparison. Your hip bone density is measured in grams per square centimeter, then compared to the peak bone density of healthy young adults. The score tells you how many standard deviations (a statistical measure of how far you sit from average) your bones fall above or below that young-adult peak.

The World Health Organization categories are simple. A score of -1.0 or higher is normal. A score between -1.0 and -2.5 is low bone mass, often called osteopenia. A score of -2.5 or lower meets the diagnostic threshold for osteoporosis. These same cutpoints apply to men and women, because at any given hip density, the average hip fracture risk is similar between sexes.

Why Hip Density Predicts Future Fractures

Among bone scan sites, the hip is the most reliable predictor of hip fracture risk, the fracture that matters most for survival and independence. The relationship is steep and consistent across populations.

• Per-point risk: In a real-world cohort of about 15,000 women, each one-unit higher total hip T-score was strongly tied to fewer clinical, nonvertebral, vertebral, and hip fractures over 24 months.
• Asian and White women: Each one-unit decline in femoral neck T-score at least doubled hip fracture risk across ethnicities in a study of nearly 274,000 women.
• Type 2 diabetes: Femoral neck T-score predicted hip, non-spine, and major osteoporotic fractures similarly in people with and without diabetes, with risk roughly doubling per one-unit drop.
• Long-term tracking: A single hip T-score predicted hip fracture risk over 25 years in postmenopausal women, with the oldest age groups carrying the highest absolute long-term risk.

The risk reduction from a higher hip T-score is not linear. It plateaus around a score of -1.5 to -2.0, which is why many specialists treat that range as a practical target for therapy rather than chasing a normal score in someone with severe bone loss.

Why Both Hips Matter (and What a Left-Only Result Misses)

Left and right hips are not interchangeable. In 3,012 women aged 50 and older, large left-right differences in hip bone density were common, with 47% at total hip, 31% at femoral neck, and 56% at the trochanter exceeding measurement error.

Scanning only one hip misses real cases of osteoporosis. About 1% of women with normal spines were osteoporotic only in the left hip, and another 1% only in the right. In stroke survivors, the side with weakness had significantly lower hip T-scores than the unaffected side, with 17% showing meaningful difference between hips. If your scan was done on the left hip only, your true bone status may be slightly better or worse than the number suggests.

Reference Ranges

These ranges come from the World Health Organization criteria used across major guidelines and apply to postmenopausal women and men aged 50 and older. Younger adults are interpreted differently (Z-scores rather than T-scores). Your lab's reference adult database can shift values slightly; newer reference data tend to classify more people as having low bone mass or osteoporosis.

Source: WHO diagnostic criteria; treatment-target observations from Banefelt 2021 and Ferrari 2019. For meaningful tracking, compare your results within the same lab and machine over time.

Beyond Fractures: Other Outcomes Tied to Low Hip Density

A low hip T-score is not just about the bone itself. It is associated with broader markers of frailty and slower recovery.

• Surgical outcomes: Adults with hip osteoporosis have more complications and revisions after total hip and knee replacement.
• Cardiovascular signals: A meta-analysis of prospective cohort studies linked lower bone density to higher all-cause and cardiovascular mortality, though not stroke mortality.
• Hidden in plain sight: In one large series of patients undergoing hip replacement for arthritis, osteoporosis was both highly prevalent and largely undiagnosed beforehand.

When Results Can Be Misleading

• Single-hip scanning: Up to half of measurements differ between left and right hips by more than the test's measurement error. If only your left hip was scanned, you may be missing osteoporosis present on the right.
• Hip hardware or arthritis: Implants, severe arthritis, or vascular calcifications in the scan field can artificially raise the apparent bone density. The number looks better than the bone really is.
• Lab and machine differences: Different DXA machines and reference databases can shift your T-score. Always compare scans done on the same machine when possible, and ask your lab whether they updated their reference dataset between scans.
• Recent fracture or surgery: Bone remodeling after a recent hip fracture or arthroplasty distorts the reading on that side.

Tracking Your Trend

A single T-score is a snapshot. The more useful question is which direction your bones are moving. Bone density changes slowly, so the value of tracking is in catching a downward trend before you cross into the osteoporotic range, and in confirming that a treatment or lifestyle change is actually working.

Get a baseline scan, then repeat in 1 to 2 years if you are starting therapy or making major lifestyle changes. Once your score is stable, every 2 years is reasonable for most adults. People on long-term steroids, with aromatase inhibitors, or with newly diagnosed conditions that affect bone should test more often. The key is using the same lab and machine each time, since left and right hips and different scanners can produce different numbers for the same person.

What to Do If Your T-Score Is Low

If your left hip T-score is in osteopenia range (-1.0 to -2.5), the next step is a FRAX assessment (Fracture Risk Assessment Tool, a calculator combining your T-score with age, weight, and clinical risk factors) to estimate your 10-year fracture risk. Treatment is typically recommended when major osteoporotic fracture risk exceeds 20% or hip fracture risk exceeds 3%, even at osteopenia T-scores.

If your score is at or below -2.5, that meets the diagnostic threshold for osteoporosis and warrants treatment regardless of FRAX. Companion tests to order alongside a low T-score include vitamin D, calcium, kidney function, parathyroid hormone, and bone turnover markers like CTX (a marker of bone breakdown). These help identify reversible secondary causes of bone loss. A bone-specialized endocrinologist or rheumatologist is the right specialist when your scan, FRAX score, or workup raises questions beyond standard care.